Japanese Unexamined Patent Application Publication No. 2002-158529 (Patent Document 1) discloses an antenna that can be used in a plurality of frequency bands and that has a configuration in which a radiation electrode is formed on the surface of a dielectric substrate.
FIG. 1 is a perspective view of the antenna disclosed in Patent Document 1. Referring to FIG. 1, a surface mount antenna 1 includes a dielectric substrate 2 shaped like a rectangular parallelepiped, a loop radiation electrode 3 and a feeding electrode 4 formed on the dielectric substrate 2. The feeding electrode 4 is formed on a bottom surface 2c and a side surface 2b of the dielectric substrate 2 in such a manner as to extend toward a top surface 2a through the side edge area of the side surface 2b. The radiation electrode 3 is formed in the form of a loop on the rectangular top surface 2a in such a manner as to extend from the feeding electrode 4 along the vicinity of the sides of the top surface 2a. An open end 3a of the loop radiation electrode 3 is arranged in such a manner as to face a feeding end side protruding electrode 18 with a predetermined distance therebetween so as to generate a capacitance between the open end 3a and the feeding end side protruding electrode.